This invention relates generally as indicated to a feedblock, and more particularly to a construction for the simultaneous extrusion or co-extrusion of two or more plastic materials. It has been found that a laminated stream of plastic material may be formed in a feedblock by feeding a plurality of heat-plastified streams into the feedblock and directing them into adjacent positions in contiguous relationship to each other. The feedblocks used heretofore have had a "stacked" construction with several plates bolted together and the passages extending through the plates. Each of the plates has been machined or otherwise cut to provide the passages from the feedports to a discharge passage where the parallel plastified streams of thermoplastic resinous material are conveyed to a discharge opening.
The feedblocks of this design have been difficult and expensive to make. The bolted construction has limited the positions in which the passages from the feedports can be located. Inspection and cleaning of the feedblocks has been difficult because it has required the removal of the several plates of the stacked feedblock. The stacked construction has also required substantial thickness of the parts to provide the necessary strength and this has resulted in a relatively heavy feedblock. Because of the relatively high cost of this construction the number of feedblocks has been kept to a minimum by designing "standard" feedblocks which can be used for several applications but do not have the most efficient feedblock design for each application.